Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020)

ONSTRUCTION

a. Rail Element for W-beam and Thrie-beam

Steel rail elements including the terminal sections shall meet the chemical and physical requirements
of AASHTO M 180 for Type II, Class B. Base metal for rail elements shall not contain more than 0.04
% phosphorous nor more than 0.05 % sulphur. For 150-mm channel rails and splice plates, the rail
elements shall meet the requirements of ASTM A36M or ASTM A992M.

Rail sections and end sections shall be form rolled to the shapes shown on the Contract plans, and
shall be hot-dipped galvanised after fabrication, per AASHTO M 111M or ASTM A123M.

Rail elements, back-up plates, reducer sections, and end sections shall conform to AASHTO-AGC-
ARTBA, A Guide to Standardized Highway Barrier Hardware, except as modified by these Standard
Specifications or the Contract plans.

All fabrication shall be complete before galvanising, including the following:

1. Holes in the plates, which shall be slotted to permit expansion and Contraction and to

facilitate erection

2. Edges of the rail, which shall be rolled or rounded so as to present no sharp edges

3. Radius of curvature less than 46 m, which shall be shaped in the fabrication shop

Each rail element shall be permanently marked per AASHTO M 180. Curved sections shall
additionally be marked

in the same manner with the radius of the curved section in the format “R =

xx m”. Markings shall be located on the back of the metal beam rail section away from traffic and
visible after erection.

Systems other than AASHTO M180 W-beam and all highway safety hardware accepted shall comply
with the Test Level-3 (TL-3) as per National Cooperative Highway Research Program (NCHR) report
350 / AASHTO manual MASH (Manual for Assessing Safety Hard-wares) crash test criteria all as
per the Engineer’s recommendations.

b. Wire Rope

Ropes for railing shall be coreless with a diameter of 19 mm. They shall have a breaking load of at
least 177 kN. Rope for railing shall exhibit a minimum modulus of elasticity of 83,000 MPa based
on an area of 283.5 mm

, after pre-stressing by an approved method, to ensure that they behave

elastically and retains tension when in service.

All wire used for the manufacture of ropes for railing shall be general purpose type II wire that has
been zinc-coated by the hot dip method as outlined in AASHTO M 30

All threaded terminals and rigging screws shall be hot dip galvanized according to AASHTO M 232.

c. Posts and Blocks

Posts and blocks shall be fabricated and installed to the dimensions, tolerances, and requirements
shown in the Contract plans. Except for terminal or anchor assemblies, all posts for any one
continuous length of guardrail shall be of the same material.

Top diameter of posts shall measure 150 mm to 230 mm, provided that posts with widely varying
diameters shall not be used together in the same length of guardrail. Posts shall be concrete, steel
or composite, as described by the material below. Blocks shall be timber, steel, or composite, as
described by the material below.

Impact performance of some features of railing system depends on dynamic soil structure
interaction. The soil shall be tested in accordance with the approved backfill and compaction criteria
as per Chapter 2, Earthworks, of these standard specifications

1. Concrete Posts

Concrete posts shall be precast in the shape and dimensions shown on the Contract plans
in accordance with the requirements of Section 4.4.8 of Chapter 4, Concrete Works.

ONSTRUCTION

Class C40/20 concrete shall be used in the construction of all concrete posts. Steel
reinforcing bars shall comply with the requirements of Chapter 5, Reinforcing Steel.

2. Steel Posts and Blocks

Steel posts shall be of the type and size shown on the Contract plans or described in the
particular specifications.

Steel posts shall be rolled sections conforming to the material requirements of ASTM A36.
Steel blocks and base plates shall conform to either ASTM A36 or ASTM A992M. Steel posts,
blocks, and base plates shall be galvanised in accordance with Sub-article d of Article 7.2.1.2.
All fabrication shall be completed prior to galvanising.

Welding shall conform to Sections 23.4.11 and 23.6.10 of Chapter 23, Steel Structures, of
these standard specifications.

3. Composite Posts and Blocks

Contractor shall provide the Engineer with the following documentation for composite posts
or blocks to be used for guardrail installations:

•

Certification that the material meets the requirements of the National Cooperative

Highway Research Program Report 350 Test Level 3 (TL-3) design speed category

•

Certification from the producer or supplier stating the material composition. Material shall

contain a minimum of 60% recycled material comprised of any combination of recycled
polyethylene; polypropylene; polyvinyl chloride; tire cord; and/or rubber, including natural
or styrene butadiene rubber

•

Certification from the producer or supplier stating that the material is thermal and process

stabilised to prevent ultra-violet degradation.

One post and one block shall be submitted by the Contractor to the Engineer for testing. Test
samples shall be accompanied by a drawing showing the dimensions of the post and block.
If changes occur in the producer, the type, dimensions, or material composition of the posts
or blocks, the Contractor shall notify the Engineer and provide additional samples for testing
at no cost to the Owner, as requested by the Engineer.

d. Galvanising and Repair

Galvanising shall be by the hot dip process in accordance with the standards identified in Table 7-3.
All fabrication shall be completed and ready for assembly before galvanising. No fabrication,
including forming, cutting, shearing, punching, drilling, bending, welding, or riveting shall be
permitted after galvanising. Galvanised guardrails shall not be nested when stacked for storage.

Table 7-3: Galvanising standards for guardrail applications

Element

Standard

Beam rail elements and terminal
sections

AASHTO M 180, Class B, Type 2

Fabricated items, rolled, pressed or
forged steel shapes, plates, pipes,
tubular items, bars, posts

AASHTO M 111M or ASTM A 123M

Bolts, nuts, washers, plates, rods,
casings, fasteners, and other hardware

AASHTO M 232M or

ASTM A 153M

Anchor cables

Federal Specification RR-W-410, Table II, galvanized
at finished size

ONSTRUCTION

Precautions shall be taken against embrittlement, warpage, and distortion in accordance with ASTM
A143M, and in accordance with ASTM A384M.

Galvanised parts shall be visually inspected by the Contractor to evaluate their fitness for the works.
Galvanising coating shall be uniform and bright. Concerns shall be addressed per Table 7-4.

Table 7-4: Appearance concerns for galvanised parts

Appearance

Remedy

White rust

(white powdery residue)

Indicates moisture

White rust shall be removed from articles that will be in
direct contact with soil and from articles where heavy
layers of white dust that have caused the coating to pit.
Light coatings of white dust shall remain or be
removed at the Engineer

’s direction.

Red rust

Indicates uncoated areas

Articles shall be inspected for gaps in coverage and
repaired or rejected at the direction of the Engineer.

Alligator cracking

(spider webbing)

Dull gray colour

Composition of the base metal may cause dark lines
or a dull gray colour. Adhesion shall be tested, as
described below, to determine whether the coating is
acceptable.

Adhesion of the coating shall be acceptable if, when tapped with a small hammer, the coating does
not scale, flake, or break.

1. Repair of Galvanisation

After  erection,  all  parts  of  galvanised  elements  on  which  the  galvanising  has  become
scratched, chipped, or otherwise damaged shall be repaired by painting it with 2 coats of high
zinc-dust content galvanising repair paint meeting the requirements of ASTM A780 / A780M
– 09, Method 2. Bare spots as wide as 3 mm across are acceptable unless they are numerous
in  the  opinion  of  the  Engineer.  Runs  or  drips  of  zinc  coating  are  acceptable  unless  they
interfere with the intended use of the product. Excessive zinc accumulations shall be carefully
hand-filed.

Surfaces to be repaired shall be clean, dry, and free from contaminants such as oil, grease,
corrosion products, and welding slag or flux. Surfaces shall be cleaned to near-white metal
by wire brushing, light grinding, or mild blasting extending into the surrounding undamaged
coating to provide a smooth repair. To attain the required dry-film thickness, the Contractor
shall spray or brush-apply the paint to the prepared area in accordance with the paint
manufacturer’s instructions. Multiple passes shall be required for spray application.

After completing repair and cooling or curing, the measured thickness of the galvanisation in
the repaired area shall be 1.5 times the thickness required for the specified galvanising up to
0.1 mm.

Paint shall not be used to repair galvanising damage caused by welding. As an alternative to
paint,  galvanising  repair  may  be  accomplished  by  zinc-based  solders  or  sprayed  zinc.
Surfaces  shall  be  prepared  as  for  paint  repair,  and  thickness  of  the  zinc  coating  in  the
repaired  area  shall  be  the  same  as  the  thickness  required  for  the  specified  galvanising.
Procedures for these 2 alternative processes shall be as follows:

i. For zinc-based solders: Preheat cleaned areas to a temperature between 315

C and 400

C. Wire-brush while heating and evenly distribute a layer of zinc solder. When repair is
complete, flush the repaired area with water or wipe with a damp cloth to remove flux
residue.

ONSTRUCTION

ii. For sprayed zinc: Apply coating by metal-spraying pistols fed with either zinc wire or zinc

powder. Provide a coating that is uniform and free of lumps, coarse areas, or loose
particles.

e. Hardware

All fastenings shall be new wrought iron or medium steel and in conformance with the dimensional
requirements of the Contract plans. Structural steel shapes, plates, bars, and strips used in
fabrication of hardware and all miscellaneous steel shall conform to the requirements of ASTM A36.

All fastenings, plates, structural shapes, bars, and strips shall be galvanised per Sub-article d of
Article 7.2.1.2.

Table 7-5: Hardware requirements and acceptance criteria

Hardware

Criteria

Acceptance

Bolts

ASTM A 307 Grade
A

Field verification and documentation that bolt heads
are stamped 307A

High-strength
bolts

ASTM A 325 Type 3

Manufacturer’s certificate of compliance**

Nuts

ASTM A 563 Grade
A

Manufacturer’s certificate of compliance**

Washers

ASTM F 844*

Manufacturer’s certificate of compliance**

Notes:
*Unless otherwise specified.
**

Manufacturer’s certificate of compliance must be accepted by the Engineer prior to installing
any of the hardware.

f. Anchors

Guardrail  end  treatments  shall  be  furnished  by  the  Contractor  in  accordance  with  manufacturer
requirements and the details shown on the Contract plans. Assembly and installation information for
the  guardrail  end  treatments  shall  by  obtained  by  the  Contractor  from  the  manufacturer;  and
installation  and  repair  manuals  specific  to  the  guardrail  end  treatments  shall  be  prepared  by  the
manufacturer and supplied to the Engineer by the Contractor.

Unless otherwise indicated in the Contract plans

or the manufacturer’s instructions, anchor

assemblies shall meet the requirements of Table 7-6.

Table 7-6: Guardrail anchor requirements

Guardrail anchor component

Requirement

Foundation tubes

Shall  be  fabricated  from  steel  conforming  to  the
requirements  of  ASTM  A500M,  Grade  B;  or  ASTM
A501.

Anchor plate assembly

Shall develop a minimum tensile strength of 178 kN.

Anchor plate and metal plates

Shall be fabricated of steel conforming to ASTM A36.

I-beam posts

Shall conform to ASTM A36 or ASTM A992M.

All metal components of the anchor and
cable assembly, including fittings, and
not less than the top 210 mm of I-beam
posts

Shall be hot-dipped galvanized in accordance with
Sub-article d of Article 7.2.1.2 of these Specifications.

ONSTRUCTION

Guardrail anchor component

Requirement

Anchor cable

Shall be 19 mm preformed, 6 wire strand core or
independent wire rope core (IWRC), galvanized, right
regular lay manufactured of improved plow-steel with
a minimum breaking strength of 190 kN.

Swaged cable fittings

Shall develop 100

% of the cable’s specified breaking

strength.

Swaged fitting and stud assembly

Shall  be  of  steel  conforming  to  the  requirements  of
AISI  C-1035,  annealed,  and  galvanized  suitable  for
cold swaging.

Cement concrete

Shall be Class C15/20 concrete conforming to the
requirements of Chapter 4, Concrete Works, of these
Standard Specifications.

Cement grout

Shall be Class G2 in accordance with Article 4.3.10.4
of Chapter 4, of these Standard Specifications.

Two certified copies of the mill test reports of the cable used shall be furnished to the Engineer. One
swaged fitting attached to 1 m of cable shall be furnished to the Engineer for testing.

g. Reflectors for Guardrail

Reflectors for guardrail shall be prismatic guardrail reflector tabs or prismatic guardrail-mounted
barrier markers and shall have the following characteristics:

1. Prismatic guardrail reflector tabs:

i. Minimum body thickness of 5 mm

ii. Galvanised steel or ultraviolet-resistant plastic

2. Prismatic reflectors:

i. 85 mm in diameter

ii.

Secured to the body in accordance with the manufacturer’s recommendations

3. Prismatic guardrail mounted barrier markers:

i. Ultraviolet-resistant

ii. Trapezoidal-shaped body

4. Post-mounted L-shaped barrier markers and flexible guardrail markers:

i. Made of a high quality impact and ultraviolet resistant, flexible, white-coloured plastic,

or similar material

ii. Minimum thickness of 5 mm

iii. Rectangular body that is flat, curvilinear, or tubular with a width between 75 mm and

100 mm

5. Minimum reflective area for L-shaped, post-mounted barrier markers shall be 645 mm

6. Reflectorized surface for flexible guardrail markers shall be 75 mm by 125 mm.

Guardrail delineator material shall be specifically manufactured to provide roadside delineation. All
delineators shall consist of complete units that are precut, pre-drilled as applicable, and ready to be
installed in the field. Delineators shall be packaged in such a manner as to prevent damage and
deterioration during shipping, handling, and storage.

A certificate of compliance stating that the reflectors comply with the following requirements shall be
supplied by the Contractor:

ONSTRUCTION

1. Retro-reflectors shall consist of a plastic face, referred to as the lens, and an opaque back

fused to the lens under heat and pressure around the entire perimeter to form a
homogeneous unit permanently sealed against dust, water, and water vapour

2. Retro-reflectors shall be of the colour shown in the Contract plans

3. Lens shall consist of a smooth front surface free from projections or indentations other than

for identification and a rear surface bearing a prismatic configuration such that it will effect
total internal reflection of light

4. Manufacturer's trademark shall be moulded legibly into the face of the lens

Specific intensity of each acrylic retro-reflector shall be at least the minimum values in Table 7-7 with
measurements made with retro-reflectors spinning.

Lenses shall have a retro-reflective area of not less than 4,195 mm

. Retro-reflection shall be

provided by the lens prismatic optical elements. To test if a retro-reflector is adequately sealed
against dust, water, or air, the Contractor shall perform the following:

1. Submerge 50 samples in water bath at room temperature

2. Subject the submerged samples to a vacuum of 127 mm gauge for 5 minutes.

3. Restore atmospheric pressure and leave samples submerged for 5 minutes.

4. Remove and examine the samples for water intake, which shall constitute a failure.

Failure of 3 or more units shall be cause for rejection of the entire lot.

Delineators shall consist of an acrylic plastic retro-reflector unit mounted in a housing fabricated of
1.60 mm 3003-H-14 or similar aluminium, or of cold-rolled, hot-dipped galvanised steel, having a
thickness of 1.62 mm. Housing dimensions, including assembly and post-mounting hardware, will
be as shown on the Contract plans or as specified in the Contract. Attachment hardware shall permit
easy removal with the proper tools, but removal shall not be possible without the use of such tools.
Housing shall be protected against corrosion, as recommended by the manufacturer.

Table 7-7: Minimum specific intensity per unit area (SIA) for clear reflectors

Observation Angle

(degrees)

Entrance Angle

(degrees)

Minimum SIA

(candelas per Lux per m

)

0.1

2,550

0.1

995

h. Inspection and acceptance of materials

Before the rail elements are fabricated, the Contractor shall notify the Engineer so that inspections
may be provided. Arrangements for facilities necessary for the inspection of material and
workmanship at the point of fabrication of the rail element shall be made by the Contractor and the
Engineer shall be allowed free access to necessary parts of the premises.

Materials or workmanship that does not fulfil the requirements of these Standard Specifications shall
be  rejected  by  the  Engineer.  Mill  test  reports  certifying  that  the  steel  used  in  fabricating  the  rail
elements meet the requirements of these Standard Specifications shall be accepted by the Engineer,
who reserves the right to require the Contractor to furnish samples of the steel proposed for use and
to  determine  that  the  steel  meets  the  requirements  of  these  specifications.  Steel  rail  elements,
fittings,  end  section  hardware,  and  bolts,  as  well as reflectors,  may  be  accepted  by  the  Engineer
based on the manufacturer’s certification of compliance.

ONSTRUCTION

7.2.1.3

Construction Requirements

Guardrail shall be installed in accordance with approved shop drawings and in compliance with the
lines, dimensions, details, and locations indicated on the Contract plans or directed by the Engineer.
Guardrail installation shall be consistent with the man

ufacturer’s recommendations.

Minimum height of the guardrail shall be 725 mm, ±25 mm measured from the top of the rail to the
finished shoulder surface.

Guardrail shall be braced to prevent movement, and all bolts shall be tightened prior to any post
holes being backfilled.

Guardrail shall be erected such that the final configuration has no projecting ends that might interfere
with or endanger traffic. Anchors and terminals shall be provided and reflectors shall be fixed in
accordance with the details shown on the Contract plans.

Any pavement damaged during guardrail construction shall be repaired as approved by the
Engineer.

a. Erection of Posts

Unless otherwise indicated on the Contract plans, all posts shall be set vertically in holes with the
diameters, spacing, and positions indicated on the Contract plans. Post holes shall be backfilled with
C30/20 concrete tamped into place or as indicated on Contract plans. After backfilling is complete
and the bracing has been removed, the posts shall be rigid and vertical; and the guardrail shall be
firmly fixed to the posts and true to line and level.

In any continuous length of guardrail, the same type of post shall be used.

When the Contract plans require that the ends of a section of guardrail be curved outward or
downward, posts shall be set to accommodate the curve. End treatment of the guardrail and length
of post shall be as shown in the Contract plans.

Posts may be placed in dug or drilled holes. Ramming or driving will be permitted only if approved
by the Engineer and if it can be accomplished without damaging the posts, pavement, shoulders,
and adjacent slopes. In broken rock embankments, pre-punching holes will be permitted only prior
to final shoulder or median compaction, surfacing, and paving. Posts shall be protected from traffic
at all times by attaching the rail elements or by a method approved by the Engineer.

When  driving  of  posts  is  approved,  it  shall  be  accomplished  in  a  manner  that  prevents  battering,
burring, separation of the galvanising from the steel, or distortion of the post. Posts shall be driven
plumb with approved power hammers or gravity hammers to the required line and grade. Approved
power hammers are steam, compressed air, vibratory, or diesel. A structural steel driving head shall
be  suitable  for  the  type  and  size  of  post  being  driven.  Wood  cushion  blocks  shall  be  used,  as
necessary, to prevent damage to the post. Rope mat, belting, or other similar cushioning material
may also be used. Any post that is bent or otherwise damaged to the extent it is unfit for use in the
finished work, as determined by the Engineer, shall be removed and replaced at no additional cost
to the Owner.

Pilot holes may be used when required or permitted. Size and depth of pilot holes shall be as
approved by the Engineer based on results of trial operations of the first few posts driven.

Where wood posts with rectangular sections are used, the posts shall be set so that the longest
dimension is perpendicular to the rail.

Posts shall be embedded a minimum of 1 m, or as shown on the Contract plans.

Post holes shall be backfilled with Class C25 concrete tamped into place in layers not to exceed 100
mm of compacted thickness, or as indicated on the Contract plans.

Where the elevation of the top surface of a culvert or other similar installation prevents the placement
of a post of the specified length, the posts shall be anchored in accordance with the details shown
on the Contract plans.

ONSTRUCTION

b. Erection of Rail

Rail elements shall be erected to produce a smooth, continuous rail paralleling the line and grade of
the roadway surface or as shown on the Contract plans.

Steel rail sections shall be galvanised per Sub-article d of Article 7.2.1.2. After galvanising, special
detail holes may be cut in the field, only when necessary and approved by the Engineer. Any holes,
nicks, gouges, or scratches in the railing’s galvanised surface shall be repaired per Paragraph 1 of
Sub-article d of Article 7.2.1.2.

Blocks shall be set so that their tops are level with the top of the post, ±13 mm, unless otherwise
shown on the Contract plans.

Bolts at expansion joints shall be located at the centre of the slotted holes. Rail plate splice joints
shall lap in the direction of traffic. Splices shall be located at posts, and spaced at intervals of 7.6 m
or less. Rail plates shall make contact over the entire area of the splice.

When nested, W-beam or thrie-beam is specified and two sections of guardrail, 1 set inside the other,
shall be installed. Inside and outside rail elements shall not be staggered.

Galvanised rail plates shall be fastened to the posts with galvanised hardware of the size and kind
shown in the Contract plans. Bolts shall be sufficiently long to extend 13 mm, or 2 threads, beyond
the nuts, or longer, where required for adjustments. Bolts extending more than 50 mm beyond the
nut shall be cut off so as to be less than 13 mm beyond the nut.

Bolts shall be tightened per the manufacturer’s installation instructions and, except where otherwise
required at expansion joints, shall be drawn tight. Bolts through expansion joints shall be drawn up
as tight as possible without being tight enough to prevent the rail elements from sliding past one
another longitudinally.

Reflectorized tabs shall be installed on posts at the locations shown on the Contract plans and
spaced at a maximum interval of 11.5 m. Slotted part of the tab shall be installed under the mounting
bolt head so that the reflectorized surface of the tab faces oncoming traffic. Exposed ends of the
slotted part of the tab shall be bent up against and then over the top of the bolt head.

Guardrail constructed under traffic shall be installed in the direction of traffic flow to constitute the
least hazard to the public.

c. Wire Rope Installation

Installation of the cable railing shall comply with the manufacturer's instructions and working
drawings for the Project.

Contractor shall install cable in continuous lengths. Before tightening bolts and finishing installation
of cables, the Contractor shall check and adjust alignment. Unless the Contract plans, particular
specification or manufacturers recommendations specify otherwise, the Contractor shall torque
bolted connections from 60 to 70 Nm. Bolts shall extend at least 6 mm but not more than 25 mm
beyond the nuts.

Contractor shall use rigging screws to join railing ropes together and to create tension. No rope shall
be longer than 154 m. Immediately in front of each anchorage, a 6 m long tail rope shall connect to
the anchorage in the ground. Both ends of every rope shall have a threaded terminal of right-hand
or left-hand thread as appropriate to ensure that rigging screws effective provide tension. Rope ends
shall insert at least 25 mm into rigging screws. A tail rope with right-hand thread on its end shall
connect to the anchor.

When all components are in place, the Contractor shall turn the rigging screws to tension ropes
uniformly to 25 kN. Contractor shall not place backfill above the tops of concrete anchor footings
before tensioning cables.

Each anchor shall have a check rope that is 1.8 m long and 8 mm diameter with a galvanized thimble
at one end and a fork terminal at the other. Such check ropes shall have a breaking load of at least

ONSTRUCTION

39 kN when tested as an assembly. Each check rope’s thimble shall pass over the end of the tail
rope and the fork terminal that is connected to the anchor.

Owner shall accept equivalent galvanised wire rope with a minimum breaking strength of at least
194 kN.

d. Terminal and Anchor Installation

Assembly and installation of guardrail anchors and terminals shall include the following:

•

Supervised  at  all  times  by  a  manufacturer’s  representative  or  an  installer  who  has  been
trained  and  certified  by  the  manufacturer.  A  copy  of  the  installer’s  certification  shall  be
provided to the Engineer prior to installation

•

As shown on the Contract plans

and in accordance with the manufacturer’s

recommendations

Terminal  anchor  posts  shall  be  backfilled  with  concrete  unless  otherwise  shown  on  the  Contract
plans.  Concrete  footings  shall  be  poured  against  moist,  undisturbed  earth.  Concrete  footing  tops
shall be smooth trowelled to slope away from the post. Immediately after placing concrete footings,
at least 100 mm of loose moistened earth free of clods or gravel shall be placed over the footing, or
the  footing  shall  be  sprayed  with  an  approved  liquid  membrane-curing  compound,  per  Article
4.3.13.2  of  Chapter  4,  Concrete  Works.  After  the  footing  has  cured,  excess  excavated  material,
including earth on top of the footing, shall be removed.

All excavation and backfilling required for installation of anchors shall be performed in accordance
with Sections 2.4 and 2.5 of Chapter 2, Earth Works, of these standard specifications. Bolts shall be
tightened to the tension specified by the manufacturer or the Contract plans. Anchor cables shall be
tightened sufficiently to eliminate all slack. When tightening, the anchor cable shall be restrained to
prevent twisting.

Where the elevation of the top surface of a culvert or other similar installation prevents the placement
of a post to the specified length, the posts shall be anchored in accordance with the details shown
on the Contract plans.

Foundation tubes used with wood breakaway posts shall be driven prior to installing the wood post.

e. Transitions

Guardrail transitions to concrete barriers or other barrier systems shall be constructed in accordance
with the details shown on the Contract plans.

f. Kerb

Where the Contract plans call for kerb with guardrail or in the transitions, kerbs shall be installed per
Section 7.5.

g. Shop Drawings

Shop drawings shall be submitted by the Contractor to the Engineer for review and approval. Shop
drawings shall be complete with all details necessary to fabricate and install the guardrail proposed
for use in the works in accordance with the manufacturer’s recommendations. Additional drawings
required by the Engineer shall be submitted by the Contractor for the Engineer

’s approval.

h. Guardrail Construction Exposed to Traffic

Any section of beam guardrail that is removed for modification shall be replaced within 5 calendar
days of the date the guardrail is removed. These operations shall be conducted in such a manner
that fixed objects and beam guardrail posts shall be protected by the Contractor from traffic at all
times by attaching the rail elements and all associated hardware or by a method approved by the
Engineer. At the end of each day, guardrail sections having an exposed end toward oncoming traffic
shall have a terminal end section bolted securely in place.

ONSTRUCTION

i. Access Control Gates

Access control gates shall be placed to line and grade as shown in the Contract plans or per the
direction of the Engineer. Gate posts shall be installed per Sub-article a of Article 7.2.1.3.

j. Removing Guardrail and Guardrail Anchors

Guardrail end treatments shall be moved or removed in accordance with the Contract plans and as
directed by the Engineer. Salvageable materials shall be handled as directed on the Contract plans
or in the Particular Specifications. Unsalvageable materials shall be disposed of in accordance with
applicable regulations.

Removal of the guardrail shall include removal of all guardrail components, including the rail, cable,
hardware, posts, transition sections, expansion sections, and terminal sections.

Removal of guardrail anchors shall include removal of the anchor assembly in its entirety, including
concrete bases, rebar, steel tubes and any other appurtenances in the anchor assembly.

All holes resulting from the removal of the guardrail posts and anchors shall be backfilled with
granular material in layers no more than 150 mm thick and compacted to the approximate density of
the adjacent material. Removed guardrail items shall become the property of the Contractor.

Every effort to reuse suitable existing guardrails rather than dispose of them and purchase new units
shall be made by the Contractor. Removal of existing guardrails shall be carried out as follows:

1. All guardrails, reflective plates, and end units shall be loosened

2. Posts shall be carefully dug out and the holes shall be filled and compacted

3. Hardware and reflectors shall be placed into bags, after which all the material shall be

transported to a store approved by the Engineer and stored in groups by type

Material intended for reuse shall be unpacked and inspected by the Engineer, who shall determine
suitability for reuse. Reusable material shall then be stored separately from material that is deemed
unsuitable for reuse.

k. Construct Guardrail from Salvage

Salvaged guardrail, guardrail transitions, anchor assemblies, and other guardrail systems shall be
constructed at the locations shown on the Contract plans in accordance with the specifications for
new guardrail.

If any salvaged materials are deemed unsuitable for reuse by the Engineer, or if the quantities of
salvaged materials are insufficient to complete the work, the Contractor shall furnish new materials
in sufficient quantities to complete the work.

Where new bolt holes in rail elements are required, the holes shall be made by drilling or punching.
Flame-cut bolt holes shall not be permitted. Galvanisation shall be repaired per Paragraph 1 of Sub-
article d of Article 7.2.1.2.

Guardrails, end units, and steel posts suitable for reuse shall be cleaned and regalvanized.

Items designated to be reused that are lost, damaged, or destroyed as a result of the Contractor's
operations shall be repaired or replaced by the Contractor at no additional cost to the Owner. Existing
posts, blocks, rail elements, or hardware that are not required for guardrail reconstruction or that the
Engineer deems unsuitable for reconstruction, shall be removed and disposed of as approved by
the Engineer.

l. Raising Guardrail

When raising guardrail anchors and guardrail terminals, the existing guardrail posts shall be raised
to attain the height shown in the Contract plans, measured from the top of the rail to the finished
shoulder surface. Material around each post shall be tamped to prevent settlement of the raised
post.

ONSTRUCTION

For raising all other guardrail, the existing guardrail posts shall not be raised to attain the new
mounting height. Existing rail elements and blocks shall be removed from the guardrail post. New
holes shall be drilled by the Contractor in the existing posts to accommodate the button-head bolts.

Any existing posts and blocks that are unsuitable for reuse shall be removed and replaced by the
Contractor, as directed by the Engineer. Voids from post removals shall be backfilled and compacted
to the approximate density of the surrounding soil. A new guardrail post shall then be furnished and
installed by the Contractor to provide the necessary mounting height.

7.2.2 Impact Attenuator Systems

7.2.2.1

Description

This work shall consist of furnishing, constructing, repairing, and removing permanent and temporary
impact attenuator systems, as shown in the Contract plans. Attenuation devices shall be approved
by the Engineer in advance of their use in the works.

This work shall include the connection to a concrete barrier, bridge abutment, or a transition section
identified in the Contract plans; the construction of a steel reinforced concrete pad or concrete
backup; and anchorage to the pavement, if required by the

manufacturer’s assembly and installation

procedures.

All impact attenuator systems accepted shall comply with the Test Level-3 (TL-3) as per National
Cooperative Highway Research Program (NCHR) report 350 / AASHTO manual MASH (Manual for
Assessing Safety Hard-

wares) crash test criteria all as per the Engineer’s recommendations.

7.2.2.2

Materials

Materials for impact attenuator systems shall be new, except undamaged sand barrel impact
attenuators that have been previously utilised, which may be used in a temporary impact attenuator
array only if inspected and approved by the Engineer prior to use.

Sand for inertial barrier systems shall not contain more than 5 % water by weight. Commercial grade
urea shall be thoroughly mixed with the sand in an amount equal to 5 %, by weight, of the sand.
Materials shall be as required by the manufacturer for proper installation of these proprietary
systems.

7.2.2.3

Construction Requirements

Attenuation devices shall be placed at the locations shown on the Contract plans or as directed by
the Engineer.

Assembly  and  installation  of  all  attenuator  systems,  except  those  utilising  sand  barrels,  shall  be
supervised at all times by either a manufacturer’s representative or an installer who has been trained
and certified by the system manufacturer. If the supervision is provided by a trained installer, a copy
of  the  installer  certification  shall  be  provided  to  the  Engineer  prior  to  installation.  Assembly  and
installation shall be in accordance with the manufacturer’s recommendations.

A complete set of replacement parts shall be provided by the Contractor on the jobsite for each type
of temporary impact attenuator in use on the project and shall repair all damaged impact attenuators
immediately.

When installation of the attenuation device is complete, all trash shall be removed from its area, and
the soil surface around it shall be graded to the elevation indicated on the Contract plans. When the
Engineer determines that a temporary impact attenuator is no longer needed, then the Contractor
shall remove that attenuator from the project. Removed equipment shall remain the property of the
Contractor.

Any welding required shall be performed in accordance with the requirements of the American
Welding Society (AWS) Structural Welding Code AWS D 1.1M.

ONSTRUCTION

Attenuators shall be removed from existing locations and stockpiled or discarded as designated on
the Contract plans or as directed by the Engineer. Salvageable units shall be cleaned and repaired
before inspection by the Engineer and delivered to the Owner storeyards. Unsalvageable or excess
materials shall be discarded in accordance with applicable regulations.

7.3 Walls

7.3.1 General

This work shall consist of furnishing all materials and fabricating and installing walls at the locations
and in accordance with the details shown on the Contract plans, the Particular Specifications, these
Specifications, and as approved by the Engineer.

All walls are presumed permanent unless otherwise specified in the Contract plans. Temporary
retaining walls shall be identified as such in the Contract plans, and are defined as those walls and
wall components constructed and removed or abandoned before the physical completion date of the
work or as shown in the Contract plans.

Areas with continuous retaining walls shall have the same facing design. To use 2 or more wall
systems, the Contractor shall provide drawings for approval by the Engineer indicating the proposed
design arrangement.

Required pile or drilled shaft foundations shall be constructed in accordance with Chapter 17, Drilled
Piles, and Chapter 18, Driven Piles, of these standard specifications, for drilled or driven piles or the
pertinent standard. Rustication, colour coating, or other treatments shall be in accordance with the
details shown on the Contract plans.

When the Contract plans call for epoxy coating of steel earth reinforcements, all steel used in
concrete panels and coping, including connectors, dowels, stirrups, and reinforcing steel, shall be
epoxy coated.

7.3.1.1

Submittals

Shop drawings and design calculations that completely describe all the information needed to
construct the wall elements and install the walls per Table 7-8 shall be submitted by the Contractor
for review and approval.

Table 7-8: Preparation, submittal, and review of submittals for walls

Shop drawings and design calculations shall be:

Prepared:

•

Under a lead

structural
Engineer

’s

direction*

•

To scale

•

Per standard

drafting procedures

•

So as to be legible

•

With all terms

defined

Submitted:

•

Enough in advance of need to

allow for the review process,
including rejection, revision, or
resubmittal

•

In accordance with Contract

requirements

•

With sufficient details to

completely fabricate and install
the element of work

•

On standard paper sizes,

typically A1, A3, or A4

Reviewed:

•

In the order the Engineer

receives them

•

In the sequence specified by the

Contractor when several
drawings or calculations are
presented simultaneously or at
the Engineer

’s discretion if no

sequence is specified.

•

Within 14 calendar days for the

first item, and within 14
additional calendar days for each
additional item submitted
simultaneously

ONSTRUCTION

Shop drawings and design calculations shall be:

* Lead structural Engineer shall have at least 10 years of experience, and/ or otherwise have a

license to practice structural Engineering in their country of origin, and shall be approved by
the Engineer.

Contractor shall comply with all submittal requirements that are applicable to each wall and shall not
begin wall construction activities, including access construction, excavation, and precast fabrication,
until receiving the Engineer

’s approval of all submittals that are applicable for that wall. Approval of

the Contractor

’s proposed wall construction details and methods shall not relieve the Contractor of

its responsibility to construct the walls in accordance with the requirements of these Specifications.

In  addition  to  the  submittals  described  in  the  following  subsections,  the  Contractor  shall  submit
excavation  shoring  drawings  to  the  Engineer  for  approval,  in  accordance  with  Article  2.4.2.11  of
Chapter  2,  Earthworks,  and  formwork  drawings  in  accordance  with  Section  1.20.8  of  Chapter  1,
General Requirements.

a. Shop Drawings and Design Calculations Submittals

For each wall, the Contractor shall submit to the Engineer for approval working drawings, details,
and design calculations that provide all of the information needed to fabricate wall elements and
install the wall in conformance with the Contract plans, these Specifications, and the direction of the
Engineer.

Any particular requirements of the approved detailed specifications for any approved proprietary
systems shall govern over conflicting or incompatible requirements contained within this section of
the specifications.

Work on an individual wall shall not commence until the Engineer has approved the required shop
drawings and design calculations for that wall. Testing of soil nails or permanent ground anchors
shall not commence until the Engineer has approved the load cell, jack, pressure gauge, and master
pressure gauge calibrations.

Shop drawings for each wall shall include, but not by way of limitation, the Contractor

’s proposed

methods and materials for all applicable items identified below:

1. Shapes and dimensions of wall elements

2. Construction sequence and method of forming precast wall elements

3. Material specifications

4. Size, quantity, and details of the following:

i. Reinforcing steel

ii.

Lifting hardware, with the manufacturer’s recommended safe working capacity, including
support point locations

iii. Additional reinforcement provided at lifting and support locations

iv. Railing and coping

v. Pads, fillers, and filter fabric, with manufacturer identified

vi. Support footings

5. Joint and joint filler details

6. Surface finish details

7. Erection block outs

8. Numbered panel layout showing horizontal and vertical alignment of the walls with existing and

proposed ground lines

ONSTRUCTION

9. Elevation view showing the following:

i. Elevation at the top of the wall, at all horizontal and vertical break points, and at least every

15 m along the wall

ii. Elevations at the base of welded wire mats or the top of levelling pads and foundations,

and the distance along the face of the wall to all steps in the welded wire mats, foundations
and levelling pads

iii. Designation of the type of panel, block, or module

iv. Location of the original and final ground line

v. Length, size, and number of geogrids or mesh or strips, and the distance along the face

of the wall to where changes in length of the geogrids or mesh or strips occur

vi. Length, size, and wire sizes and spacing of the welded wire mats and backing mats, and

the distance along the face of the wall to where changes in length, size, and wire sizes
and spacing of the welded wire mats and backing mats occur

10. Plan view showing the following:

i. Offset from the construction centreline to the face of the wall at all changes in horizontal

alignment

ii. Limit of the widest module, geogrid, mesh, strip, or welded wire mat

iii. Centreline of any drainage structure or drainage pipe which is behind or passes under or

through the wall

iv. Actual lengths proposed for the reinforcing layers and the locations of each product

proposed for use in each of the reinforcing layers

11. General notes required for design and construction of the wall

12. All horizontal and vertical curve data affecting wall construction

13. Summary quantities of those items on the elevation sheet of each wall, including incidental

items

14. Cross sections showing limits of construction. In fill sections, the cross section shall show the

limits and extent of select granular backfill material placed above original ground

15. Limits and dimensions of reinforced soil volume

16. Contractor

’s proposed wall construction method, including proposed forming systems, types

of equipment to be used, proposed erection sequence and details of how the backfill will be
retained during each stage of construction

17. All details needed to do the following:

i. Incorporate or connect to coping, railing, drainage features, conduit, sign, signal, luminaire

or other required elements

ii. Bend steel reinforcing bar, per Section 5.4.1 of Chapter 5, Reinforcing Steel.

iii. Construct foundations and levelling pads, including details for steps in the foundations or

levelling pads, as well as allowable and actual maximum bearing pressures for AASHTO
load groups I and VII

iv. Construct all modules and facing elements. Details shall show all dimensions necessary

to construct the element, all steel reinforcing bars in the element, and the location of
reinforcement element attachment devices embedded in precast units

v. Traffic or pedestrian barrier at the top of the wall, if shown in the Contract plans, including

interaction with bridge approach slabs

ONSTRUCTION

18. Method and equipment used to support precast wall elements during storage, transporting,

and erection

19. Erection sequence, including method for lifting panels, placing and adjusting panels to proper

alignment and grade, and supporting panels during bolting, grouting, and backfilling operations

20. Levelling pad elevations, which may vary from the elevations shown on the Contract plans.

Unless otherwise indicated, at least 300 mm of cover from the top of the levelling pad to
finished grade shall be provided

21. Shop drawings for all structural steel wall elements, including steel soldier piles and

permanent ground anchors

25. Rate of placing concrete so as to prevent cold joints, considering the wall thickness, height,

and volume of concrete to be placed

Design calculations for each wall shall include, but not by way of limitation, all items that apply to the
following:

1. Calculations for precast wall elements

2. Calculations for the connection between the precast wall elements and the cast-in-situ footing

3. Calculations for modifications to the cast-in-situ footing details as shown in the Contract plans

4. Calculations for the range of heights and loading conditions on the Project

5. Calculations for internal and external stability as described in the Contract plans

6. Summary of all design parameters used

7. Material types, strength values, assumed allowable loads and loading combinations

8. Factor-of-safety parameters

b. Wall Access Plan Submittals

If construction of a wall requires access for work activities, then the  Contractor shall submit to the
Engineer  for  approval  a  wall  access  plan,  which  shall  include,  but  not  by  way  of  limitation,  the
following:

1. Locations of access to the wall construction sites

2. Method, materials, and equipment used to construct the access, remove the access, and

recontour and reseed the disturbed ground

c. Shaft Installation Plan Submittals

For construction of walls with shafts, the Contractor shall submit a shaft construction plan to the
Engineer for approval at least 14 days in advance of the proposed start of work. Shaft installation
shall not begin until the Engineer

’s approval of the shaft installation plan is received.

Submittals shall comply with the applicable requirements of Chapter 17, Drilled Piles, and Chapter
18, Driven Piles, of these standard specifications.

Manufacturer’s Certificate of Compliance

Unless acceptance of materials is defined otherwise in these specifications, the Contractor shall
furnish to the Engineer

a manufacturer’s certificate of compliance with each shipment of materials,

certifying that the materials conform to the specified material requirements. A copy of all test results
necessary to assure compliance with the Specifications, shall be submitted to the Engineer along
with each manufacturer’s certificate of compliance.

7.3.1.2

Shaft Foundations

Shaft foundations shall comply with the requirements of Chapter 17, Drilled Piles, and Chapter 18,
Driven Piles, of these standard specifications.

ONSTRUCTION

7.3.2 Boundary Walls

7.3.2.1

Description

This work constructs boundary walls, also called perimeter walls or privacy walls, including the
following different types:

1. Reinforced concrete walls (refer to Chapter 4, Concrete Works, of these Standard

Specifications)

2. Precast post and panel walls, which use precast grooved posts with precast panels slid into

the post grooves after the posts are erected, or use of a tilt-up-type panel construction where
the posts are cast-in-situ after the panels are set upright

3. Reinforced posts and upper frame with concrete block infill and plastered decorative finish

4. Walls with openings having decorative aluminised grill panel

Boundary walls, as addressed in this section of these standard specifications, are not retaining walls.
Boundary walls that are required to retain material shall be constructed as retaining walls in
accordance with Chapter 20, Earth Retaining Systems, of these Standard Specifications.

Decorative lighting for boundary walls shall conform to the requirements of Particular Specifications.

7.3.2.2

Materials

Concrete shall be of the compressive strength shown on the Contract plans and shall conform to the
applicable requirements of Chapter 4, Concrete Works, unless otherwise shown on the Contract
plans.

1. Concrete for precast wall panels shall be Class C30/20.

2. Concrete for shafts shall be Class C30/20P.

3. Concrete Class C30/20W shall be used for shafts placed in water.

4. Concrete for trench, grade beam, or spread footing foundations shall conform to Class C30/20.

Materials shall conform to the requirements of the Contract plans, as approved by the Engineer, and
these Specifications, including those sections specifically noted in Table 7-9. Other materials
required shall be as specified in the Particular Specifications.

Table 7-9: Materials for boundary walls

Material

Specifications Requirements

PCC and its constituent materials; steel
reinforcing bar; premoulded joint filler and
waterstops.

Section 4.3 of Chapter 4, Concrete Works, and
Section 5.3 of Chapter 5, Reinforcing Steel

Bolts and nuts shall be stainless steel.

ASTM F738M

Paints.

Chapter 24, Painting

Gravel backfill.

Section 2.5 of Chapter 2, Earthworks

Pipe underdrains.

Section 12.1.3 of Chapter 12, Stormwater
Drainage

Decorative wall finishes.

Section 7.8

Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020) - page 44